1. Field of the Invention
The present invention relates to a bone connecting tool for connecting a corpus vertebrae and a connecting member used in the bone connecting tool, and more particularly to a bone connecting tool which can properly and stably keep a positional relationship between the corpus vertebrae and the connecting tool, and a connecting member thereof
2. Description of the Related Art
In the case of connecting a corpus vertebrae such as a lumbar vertebrae or the like, there is executed a method of screwing and inserting respective screws to apart bodies of vertebrae in a corpus vertebrae, respectively engaging one end side and another end side of a rod with engagement grooves formed in a head portion of the respective screws and fixing both end sides of the rod to both screws by a fixing screw. Further, there is employed a structure of supporting and fixing both end portions of the rod by a hook member provided with a hook portion freely hooked to an arch of vertebrae in the corpus vertebrae.
In the structure of screwing and inserting the screws to the bodies of vertebrae in the corpus vertebrae and supporting both end portions of the rod by the screws, it is necessary to screw and insert the screw to the corpus vertebrae in an accurate direction and at an accurate depth, so that there is a problem that it is hard to screw and insert the screw.
In the structure of hooking the hook portion of the hook member to the arch of vertebrae in the corpus vertebrae and supporting and fixing both end portions of the rod by the respective hook member, it is unnecessary to screw and insert the screw to the corpus vertebrae. However, since the hook portion in the hook member is simply hooked to the arch of vertebrae, there is a problem to be improved in view of improving a stability.
The present invention is made by taking the problems described above into consideration, according to a first aspect of the present invention, there is provided a bone connecting tool for interconnecting vertebral bodies comprising: a rod engaging member attachable to an arch of vertebrae in a corpus vertebrae; and a rod member having a rod portion freely fixed to the rod engaging member, wherein a projection portion for eating into the arch of vertebrae is provided in the second hook portion provided in the rod engaging member.
Moreover, the structure may be made such that the rod member is provided with a processus spinosus in the corpus vertebrae or a first hook portion freely hooked to the arch of vertebrae in one end portion thereof, and a projection portion for eating into the processus spinosus or the arch of vertebrae is provided in the first hook portion.
Moreover, there is provided a bone connecting tool comprising: a hook member freely hooked to an arch of vertebrae in a corpus vertebrae; and a connecting member having a rod portion freely fixed to the rod engaging member, wherein the rod member is provided with a processus spinosus in the corpus vertebrae or a first hook portion freely hooked to the arch of vertebrae in one end portion thereof, and a projection portion for eating into the processus spinosus or the arch of vertebrae is provided in the first book portion.
Moreover, the rod member in the structure described above is structured so as to have a substantially V shape or J shape, and is provided with a projection portion inside a bent portion.